[C#] Schiefer Wurf

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework;

namespace WindowsPhoneGame1
{
 class Enemy
 {
 //Enemy Texture
 Texture2D enemyTexture;

 //Enemy Position
 public Vector2 position;

 //State of Enemy
 public bool active = true;

 //startspeed and angle
 private int v = 100;
 private int angle = 45;

 //Gravity
 float g = 9.81f;

 //t für den schiefen Wurf
 float t = 10;

 public void Update(GameTime gameTime)
 {
 //Elapsed Time since the game started
 float time = (float) gameTime.ElapsedGameTime.TotalSeconds;
 float x = (float)(v * Math.Cos(angle) * t);

 t += time;
 
 position.X = x;
 position.Y = (float) (v * Math.Sin(angle) * t - 0.5f * g*t*t);
 //position.Y = (float) -(g / (2 * Math.Pow(v,2) * Math.Pow(Math.Cos(angle),2)) * Math.Pow(x,2) + Math.Tan(angle) * x);
 }

 }
}